Improvement in portable burglar-alarms



UNITED STATES PATENTOFFICE.

JAMES H. THORP, 0F ST. LOUIS7 MISSOURI.

IMPROVEMENT IN PQRTABLE BURGLAR-ALARMS.

Specification forming part of Letters Patent No. 139,440, dated M ay 27,1873; application led March 12, 1873.

To all whom it may concern:

Be it known that I, JAMES HARRY Tnonr, of St. Louis, in the county of St. Louis and in the State of Missouri,have invented certain new and useful Improvements in Burglar-Alarm 5 and do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon making a part of this specification.

The nature of my invention consists in the construction and arrangement of a device attached to, and forming part of, a burglar-alarm, whereby, when the alarm is placed on the floor, inside of the door, and the door partially opened, the alarm Will be sounded, and the door stopped in its inward movement, as will be hereinafter more fully set forth.

In order to enable others skilled in the art to which my invention appertains to make and use the same, I will now proceed to describe its construction and operation, referring to the annexed drawing, in which- Figure l is a side view, a-nd Fig. 2 a longiiudinal section, of a burglar-alarm with my device attached to the same.

A represents the casing, with bell B a-nd clock-work C, to be wound up bymeans of a key, said parts being constructed inauy dcsired manner. The clock-work C is provided with a detent, D, which extends through a slot in the casin g, and is so arranged that when its outer end is elevated the clock-work will be stopped, but as soon as the outer end of the detent is depressed it will be started and sound the alarm. In the easing A, below the detent D, is hinged a bar, G, with another bar, G', hinged at its outer end, and said bars .y are of such size that they can be folded under thecasing when the alarm is not in use.

When the alarm is to be used, the bars G Gr are thrown out in the manner shown in the drawing, the outer or free end of the bar G resting upon the end of the detent D. The alarm is then placed on the iioor, inside of the door, in such a position that, as soon as the door is opened, the door will move upon the incline formed by the bar G' and press the same down, which depresses the outer end of the detent D and sets the alarm going.

On the under side of the bar Gr are small points or teeth ct a, to catch in the floor or carpet, to prevent the alarm from being moved inward by the door; and on the under side of the bar G are larger teeth or points b b which,

as said bar is pressed downward by the door,

are forced through apertures z' in the lower bar G into the floor, and as a consequence stop the inward movement of the door.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

In combination with an alar1nbell the bar Gr, hinged to the ease of the bell and provided with teeth a a and holes z' c', and the bar G hinged to the outer end of the bar G and provided with teeth b b, all constructed and arranged as described, so as to be folded within the ease when the alarm,l is not in use, and operate upon the detent of the bell when in use, as herein set forth.

In testimony that I claim the foregoing I have hereunto set my hand this 14th day of February, 1873.

JAMES HARRY THORP.

Witnesses: A

C. L. EVERT, A. N. MARR. 

